Braking apparatus for roller conveyers



April 1, 1952 McKAY 2,590,994 7 BRAKING APPARATUS FOR ROLLER CONVEYERS Filed Aug. 26. 1949 4 She'e ts-She'et l Inventor: J05PH MrmY,

April 1,1952 J. McK 2,590,994

BRAKING APPARATUS'FOR. ROLLER CONVEYERS.

Filed Aug. 26. 1949 4 Sheets-Sheet 2 Inventor: J055P Mex m,

April 1, 1952 r J MCKAY 2,590,994

BRAKING APPARATUS FOR ROLLER CONVEYERS Filed Aug. 26. 1949 4 Sheets-Sheet 3 I a a 1420811501: J05PH Mc/(mi April 1 1952 J, McKAY 2,590,994

BRAKING APPARATUS FOR ROLLER CONVEYERS Filed Aug. 26. 1949 4 Sheets-Sheet 4 I 1@ F' M 56 A Q lawenior: T 8 J05PH Max m,

$1 J AWAM wwmg Patented Apr. 1, 1952 BRAKING APPARATUS FOR ROLLER,v

. CONVEYERS.

Joseph McKay, Port Vue, Pa. ApplicationAugust 26, 1949, Serial No. 112,540v

4 Claims. I

This inventionv relates to conveyors. and, in

particularr to a brakemechanism for a gravity roller table including side. rails. and transverse rollers, the rails being, notched. or. slottedidownwardl'y from their upper edges for removably receiving thiiendsof the roller. shafts.

In certaininstances, it. is. desirable to restrain or arrest the rotation of. some of the rollers of a gravity ;roller table in order to spot. a load thereon at approximately agiven location. One

example is; the. section of conveyor mounted on a scale. beamfor the purpose of weighing loads moving along the conveyor in succession. The provisiongof' brakes for the rollers presents a serious problem however, in. cases where the rollershave their shaft endsseated in slots opening.

downwardly from the. upper -edges. of'the side rails. in order to permit. ready removal and replacement of'rollers.

I have-invented a novel brake mechanism particularly suited. for the rollers of atable off the characterWdescribed, although it may. also be used withia conveyor the side'rails of which have holes therein for accommodating the ends of the roller shafts. In apreferred embodiment, I provide one pr more pairs of adjacent rollers with an elongated wedge block tapering downwardly, disposedjlongitudinally in the space between the pair of rollers and so related thereto that on. relative vertical movement between the rollers and block, th" peripheries of the former will be eni'onally by the latter, therebyfei erting action. The wedge block may ibe provided wit hi actuating means or it may be mounted. so as torbiecome effective on. upward movement of the-table.

A complete understanding of theinvention may be obtained from the following detailedjdescription andlexplanation which refer to the: accompanyingdrawings illustrating apresenti preferred embodiment and a modification; In the drawings,

Figure 1 is a central longitudinal section through a portion of a gravity roller table having theinvention applied thereto;.

Figures 2, 3 and 4, respectively, areztransverse sections taken along the planes Iii-11; III --III and IV -IV of Figure 1; g Figure 5 is a view similar to Figure 1 showing a modification;

Figure 6 is a transverse section taken along the plane of line VI-VI of Figure 5; and

Figure '7 is. a portion of Figure 5 shown to eniar ed scale.

Referring now in detail to the drawings and,

for the present to Figures 1 through 6, aroller conveyor table II) includes aligned portions or sections l0, l0 ori I0 forming, a continuous.

downwardly slopingpath for. the transport of articles placed thereon, by gravity. The invention is illustrated as applied to the section (0 which is supported independently of the sections Ill and Ill in. order to permit weighing of the articles passing along the conveyor when arrested or spotted by the aid of my'invention, the entire section l0 beingcarried on the beams of a weighing scale, not. shown. It is to be under.- stood, however, that the invention may be ap--. plied equally well to} any permanently mounted portion of the conveyor on which it is desired to decelerate or arrest the articles traveling along the conveyor. Conveyor sections Ill and [0 are of'conventional construction and. the following description will therefore be confined to section In". f

Conveyor section lfl proper comprises two sets ofparallel rollers II and I2 journaled respectively in pairs of spaced angles 3. The table may. of

course, be designed with a single setofangles and is mounted for limited tilting movement aboutv one end. For this purpose. the frame is provided with hinge brackets lg Cooperating hinge brackets l9 are mounted'on-a subframell! composed of longitudinal membe' 10 and transverse members 20". A pivot sh 21 extends through bearings forming part of each of the brackets II and 19. The subframe 20;; incidentally, is supportedby the scale beams as previously mentioned. Bearing blocks 22 located on subframe 20' at the end of conveyor section Ni opposite the pivot shaft 21 normally support the frame H in the plane of the conveyor table which is generally horizontal but slopes" downwardly toward the right so that articles placed on the rollers will travel along the conveyor by gravity.

In order'to prevent an article which has been arrested on the section 10' byymy brake means to bedescribed in detail shortly, from starting along theconveyor before completion of the weighing operation, I provide means for temporarily tilting the: frame I 4 counterclockwise about pivot.

sition in whichitv is shown. This means. com-- prises a pair of fluid-pressure cylinders and pistons 23. As shown in Figure 4, the cylinders are pivotally connected to the frame M by trunnions 24 extending laterally therefrom into bearings 25 and 25 mounted in the frame adjacent the righthand end thereof. For mounting these bearings the frame is provided with additional cross beams 26 and short lengths of longitudinal beams 21 and 2| extending between them. The piston rods of the cylinders are pivoted to bearings 28 supported on the cross beams 20 of subframe 20.

The frame l4 includes intermediate cross beams 29 spaced below the longitudinal beams I by blocks 30 as shown in Figure 3. Fluid-pressure cylinders 3| are mounted vertically on each cross beam 29 with their piston rods extending upwardly. A yoke 32 is pivoted to each piston'rod by a pin 33. Each yoke includes a horizontal beam 32 and a pair of posts 32 extending upwardly therefrom, one at each end. The upper ends of these posts are turned downjan'd threaded as shown. An elongated. Wedge block 34 tapering downwardly is mounted on each'post 32 and secured thereto by a nut threaded on the reduced upper end thereof. The posts 32 and the associated. parts are so dimensioned that, when section ID? of the roller table is in horizontal position, the tops of the wedge blocks when in their uppermost position, will lie below the plane tangent to the rollers H and I2 at the tops thereof. The wedge blocks are disposed in the space between pairs of adjacent rollers and normally engage them with their tapering sides, under the weight of the blocks and associated parts but will not exert suflicient friction thereon to retard them materially.

The supply of operating fluid to the cylinders 3| is controlled bya solenoid valve 35 and it is in turn controlled by suitable push buttons and electric circuits (not shown) as well understood in the art. The control system is preferably so designed that the power fluid, ,e. g., compressed ain i's'fj admitted to the lojwerendsof the cylinders and exhausted from the upper, ends when one push button (release) is pressed, and vice versa when the other (?"brake) button is pressed. That is to say, the severalblocks-are either supported in their uppermost position in which they have little or no contact withthe rollers or are urged downwardly by ,the fluid pressureon the pistons of the cylindersflto 'eifect frictional engagement with rolls and exert braking action thereon, depending on which button is pressed. .When neither push buttonis pressed, both ends of the cylinders are connected to exhaust and the wedge blocks ride lightly on the rollers suspending the weight of theyokes 32 but, as explained above, this does not cause any effective braking action on the rollers. 1

In order that the braking effect may be applied or releasedin either thefup. (horizontal) posi-. tionofthesection I0 v or the down (inclined) position, the cylinders 3| should have a stroke exceeding that of cylinders 23. The number of the cylinders 3| and associated wedge blocks may bevaried if necessary to secure the desired'braking effect. While two pairs of cylinders are shown in the drawings, eachoperating .two wedge blocks, three pairs of cylinders are providedfor in a design developed for an actual installation. s

In normal operation of the apparatus described above, the section Ill of the roller table is in its down or inclined position with the beam 26'at the right-hand end restingon theposts 22. On the approach of an article along conveyor section I0, cylinder 23 is operated to raise the section [0 to horizontal position. The cylinders 3| at that time are connected to exhaust at both ends (unless'the "release push button is pressed) and the wedge blocks ride lightly on the rollers. When the article has almost reached the desired position on the section I0 the brake button is pressed and cylinders 3| are operated to cause the wedge blocks to engage the rollers under considerable pressure, thereby applying a braking effect thereon and decelerating the article which eventually comes to rest. The weight of the article indicated on the scale is then noted, after which the release button is pressed momentarily, relieving fluid pressure from the upper ends of the cylinders 3| and applying it to their lower ends to lift the wedge blocks. The cylinders 23 are then operated to lower the table to inclined position whereupon the article on section I0 is started by the acceleration of gravity and continues to travel along the conveyor passing from section I0 to section |0. i

It will be appreciated from the foregoing that, in the preferred embodiment, illustrated in Figures 1 through 4, the wedge blocks may be rendered effective to exert braking action on the rollers engaged thereby, whether the table section Ill is in its inclined or horizontal position. A modified form of the invention shown in Figures 5'and 6 is of such character'to apply the braking action automatically when thejtable section is raised to horizontal position and re; lease itwhen the table is lowered to permit continued travel of the article. 1 1 Referring in detail to Figures 5 and 6, the roller table section there illustrated and the mounting thereof are generally similar to the structurefal ready described except that the longitudinal members of .the frame M, are composed of only a single beam l5. Wedge ,blocks 36, similar'to the blocks 34, are supported'on. vertical rods 31, each block having and adjacent each end thereof. The rods 31 include upper and lowerportions connectedby a helical tension spring 38 disposed coaxially thereof and secured thereto. Thelower ends of the rods 31 are threaded and pass'through holes in cross bars 39 extending be'-' tween the longitudinal members of the subfram'e 20. The rods are adjustable verticallyfon the crossbar 39 by means of nuts 40. Therods 3! are adjusted so that, whenthe table section Ill israised to horizontal position (the position in which itis. shown in Figure 5) by cylinders.,2 3, the blocks 36 will engage the adjacent rollers" and the springs 38 will be,elongated slightly to exert a yielding downward force on the blocks. When, the table section is lowered to inclined position, the springs 38 will be fully collapsed and support the. blocks 36 out of cone} tact with the adjacent rolls. .The overall effect of this construction is that the brakes are applied when the table section is raised.to horizontal position, thus arresting an article traveling there-.. along preparatory. tov weighing it. After the weighing operation, lowering of the table, section to inclined position, releases the braking .lefiect automatically and permits the article to con-. tinueitstravel.

,- Figure 7 illustrates a modification inthe form of therollers providing increased brakingaction. According .to' this modification, the plain or. smooth rollersull and. i2 are ,replacedby rollers 4| having longitudinal grooves 42 spaced around length engaged'by the wedge blocks 34 or as.

These grooves increase the frictional resistance to turning of the rollers on engagement thereof by the wedge blocks. A still further increase of such resistance may be obtained by providing the sides of the wedge block with longitudinal ridges giving them a saw-tooth contour.

It will be apparent from the foregoing that the invention provides effective braking means for conveyor tables having rollers journaled in slots formed in spaced side rails for the sake of easy removal and replacement. The application of braking action is effected by a downward pull on the wedge blocks but all portions of the mechanism are always maintained below the level of the tops of the rollers avoiding interference with the travel of articles along the conveyor when the brakes are released. The braking action is under manual control independent of the position of the tilting table section in the case of the preferred embodiment and isapplied automatically in the case of the modified construction. In both cases, the construction is relatively inexpensive and easy to maintain.

I claim:

1. Braking apparatus for a gravity roller conveyor made up of an elongated frame and a plurality of parallel rollers journaled transversely in said frame in spaced relation along the length thereof, said apparatus comprising an elongated block of wedge shape disposed with its narrower edge down and located between two adjacent rollers parallel thereto, the maximum width of the block being greater than the distance between said adjacent rollers at their nearest to engage said adjacent rollers with its sides, the

thickness of the block being such that the top thereof is below the plane tangent to the rollers at the top thereof when the sides of the block are out of engagement with said adjacent rollers and means mounting said frame and block for movement of one of them in a generally vertical direction relative to the other whereby to cause the sides of the block to engage said adjacent rollers.

2. The apparatus defined by claim 1 characterized by said means being a hinge on which the frame is tiltable, saidhinge being offset along the frame from said block.

3. The apparatus defined by claim 2 characterized by a yielding support for said block extending upwardly from below said frame.

4. The apparatus defined by claim 1 characteriz'ed by said means being a support on which said block is carried, and power means for raising and lowering said support.

JOSEPH McKAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 655,505 Morrow Aug. 7, 1900 1,900,149 Anderson Mar. 7, 1933 1,905,379 Gotthardt et a1. Apr. 25, 1933 2,118,195 Hague May 24, 1938 FOREIGN PATENTS Number Country Date 781,301 France Feb. 18, 1935 

